Azarbakht Banakdeh, Alireza ORCID: 0000-0003-3627-652X and Douglas, John ORCID: 0000-0003-3822-0060 (2022) Variations in uniform hazard spectra and disaggregated scenarios during earthquake sequences. Bulletin of Earthquake Engineering, 21 (1). pp. 77-94. ISSN 1570-761X (doi:https://doi.org/10.1007/s10518-022-01540-7)

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Abstract

Seismic hazard varies greatly during an earthquake sequence. Understanding this variation
can be useful to end-users, such as emergency managers, as it would enable them to make
more informed decisions about potential risk reduction measures. This article presents
examples of how two commonly-used products of probabilistic seismic hazard assess-
ments: uniform hazard spectra and disaggregated earthquake scenarios, vary during two
severe seismic sequences in western Greece. These calculations are made using a recent
time-dependent seismic hazard model based on a Bayesian ETAS approach. The examples
show that time-dependent uniform hazard spectra for short return periods (1 and 10 years)
are significantly higher than standard time-independent spectra but that uniform hazard
spectra for the commonly-used return periods of 475 and 2475  years are similar to those
from time-independent assessments. The time-dependent spectra generally converge within
a couple of days to the time-independent spectra. The examples also show that the domi-
nant earthquake scenarios evidenced by the disaggregation for the time-dependent assess-
ment can show significant differences from the time-independent scenarios. This is par-
ticularly true when the earthquake sequence is distant from the location of interest as the
aftershocks contribute greatly to the overall hazard. To show these changes more clearly
this article introduces a new graphical representation of the disaggregated results: contour
maps showing the magnitude or distance of the dominant earthquake scenario with axes of
the structural period and response spectral acceleration.

Item Type:	Article
Uncontrolled Keywords:	Time-dependent PSHA · Disaggregation · UHS · Seismic sequence · Dominant earthquake scenario · Greece
Subjects:	Q Science > Q Science (General)
Faculty / School / Research Centre / Research Group:	Faculty of Engineering & Science
Last Modified:	18 Apr 2023 12:31
URI:	http://gala.gre.ac.uk/id/eprint/41376

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